1. Field of the Invention
The present invention relates to an image processing device for combining a plurality of images such as taken images, an image processing method, and an imaging device.
2. Description of the Related Art
An image processing device, such as a digital camera, is sometimes installed with an image combining (multiple exposure) function for combining a plurality of JPEG images or RAW images by addition after adjusting brightness by multiplying the plurality of images by a coefficient, and generating an image so as to depict a plurality of scenes with a single image.
For example, Japanese patent No, 3800192 (published Jul. 26, 2006) discloses an imaging combining device where, in the case of combination using an image that has been subjected to image processing, such as a JPEG image, by carrying out combination by converting to an image before image processing, and carrying out image processing again, the effects of gamma conversion etc. are eliminated. Also, Japanese patent laid-open No. 2010-124411 (laid-open Jun. 3, 2010) discloses an image processing device that is capable of image combining with WB corrected, even in the case where taken RAW images have different light sources, by combining image data that has been subjected to predetermined white balance (hereafter referred to as “WB”) correction with respect to RAW images.
With an imaging device such as a digital camera, a light source is automatically estimated at the time of shooting and various WB modes are provided, such as auto white balance (AWB) mode for appropriately correcting WB, preset WB mode in which a user selects a mode in accordance with the light source, and one touch WB where WB is matched to a specific subject, with WB correction being carried out in accordance with the WB mode that has been selected by the user.
By selecting WB mode appropriate to the light source at the time of shooting, or AWB mode, it is possible for the user to take a picture in which WB of an achromatic (white or gray) subject has been ascertained. Also, by intentionally selecting different WB modes, it is possible to impart color to an achromatic subject. In this way, it is possible to change the color cast of a photograph by progressively setting the WB mode.